Various hybrid and electric powertrain architectures are known for managing the input and output torques of various prime movers in hybrid vehicles, most commonly internal combustion engines and electric machines. Hybrid electric vehicles utilizing both an electric machine and an internal combustion engine as power sources often have an onboard controller programmed to vary use of each of the engine and motor/generator during different driving conditions, and can be controlled to achieve peak efficiency and/or peak performance in different operating modes.